Psychoacoustic Assessment of Noise under a Motorcycle Helmet
Psychoacoustics is a dicipline that has been applied to many products of real life. Especially psychoacoustic metrics are uses in the automotive industry. In opposite psychoacoustics have not been applied to motorcycle helmet noise, yet. After first approaches to quantify the sound pressure level for helmets in the last years, the psychoacoustic investigation is a consequent step. For evaluating the product sound quality of motorcycle helmets and to increase the acoustic comfort for the motorcyclists thereof, a series of on-road trials using a combination of different helmets, vehicle speeds, and riding positions were performed. An arbitrary magnitude digital filter to equalize was used for the frequency-varying calibration response of the in-ear microphones.After this technical necessary step the accurate objective psychoacoustic quantification was possible. In parallel the subjective perception of the helmet has been determined by an jury test.The main effect plots reveal that all the three predictor variables used in the measurement contributes significantly to the overall sound pressure level and other psychoacoustic metrics. An analytical association between the objective and subjective psychoacoustic assessments using a statistical linear regression analysis model correlated the metrics loudness, sharpness, roughness and articulation index at 75%, 85%, 48% and 68% respectively.